The emergency Metal Key blade with Transponder chip is for the Door Open & Start engine, if the remote fob is broken or Lost or Car battery goes flat. (emergency situation )
https://www.jdm-parts.co.nz/mazda-verisa-lost-card-key-signal-and-lost-key-blade/?feed_id=103496&_unique_id=668ff82464477Replacement Key Programming
MAZDA Verisa Lost Card Key Signal and lost physical key Blade
MAZDA Verisa Lost Card Key Signal and lost physical key Blade